1. Field of the Invention
The present invention relates to scroll compressors that may compress a fluid (e.g. a refrigerant gas) by utilizing stationary and movable scrolls and discharge the compressed fluid through a discharge valve. The present invention particularly relates to scroll compressors that do not require a bolt to affix the discharge valve to the movable scroll. The present scroll compressors may be advantageously utilized in a vehicle air conditioning system.
2. Description of the Related Art
A known scroll compressor is disclosed in Japanese Laid-open Patent Publication No. 11-2194 and includes a stationary scroll and a movable scroll. A compression chamber is defined by a space between the stationary scroll and the movable scroll. When the movable scroll orbits with respect to the stationary scroll, the volume of the compression chamber is reduced and thus, the fluid drawn into the compression chamber is compressed and discharged from the discharge port. The discharge port is disposed within the movable scroll at the location corresponding to the compression chamber in its minimum volume. The discharge port opens and closes by means of a reed-type discharge valve. When the discharge valve closes the discharge port, backflow of the compressed fluid into the compression chamber can be prevented. The discharge valve includes a reed valve and a retainer for the reed valve. A bolt affixes the reed valve and the retainer to the base plate of the movable scroll at a position that is on the opposite side of the stationary scroll.
Labor-intensive work is necessary to affix the bolt. Moreover, because the thickness of the base plate of the movable scroll is increased due to the bolt that connects the discharge valve to the movable scroll, the space proximal to the discharge port must be increased and accordingly, dead volume increases. The increased dead volume decreases compression efficiency.
It is, therefore, an object of the invention to provide improved scroll compressors that do not require a bolt to couple or affix the discharge valve to the movable scroll.
In representative scroll compressors according to the present teachings, a discharge valve may preferably be coupled or affixed to a movable scroll by means of a discharge valve clamping device that extends between a bearing member and the discharge valve. Further, the discharge valve clamping device may prevent the discharge valve from moving together with the bearing member if the bearing member unintentionally or accidentally revolves or orbits together with the drive shaft member and independent from the movable scroll. For example, the bearing member may revolve independently of the movable scroll if the bearing member is pressure-joined (frictional fit) to the movable scroll and if the bearing member separates from the movable scroll due to differences between the thermal expansion co-efficient of the bearing member and the movable scroll. Naturally, the thermal expansion coefficient may differ if different materials are utilized to construct the bearing member and the movable scroll.
According to the present teachings, the discharge valve can be securely positioned with respect to the movable scroll because the discharge valve is prevented from moving together with the bearing member even if the bearing member unintentionally or accidentally revolves or orbits together with the drive shaft member and independently from the movable scroll. An advantageous feature of the present teachings is that a bolt is not required to couple or affix the discharge valve to the movable scroll.
Other objects, features and advantage of the present invention will be readily understood after reading the following detailed description together with the accompanying drawings and the claims.